content: /* Copyright (C) 2016-2018 Alibaba Group Holding Limited
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  
  // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  import protobuf_unittest.NonNestedExtension;
  import protobuf_unittest.NonNestedExtensionLite;
  import java.lang.reflect.Method;
  import java.net.URLClassLoader;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  import junit.framework.Test;
  import junit.framework.TestCase;
  import junit.framework.TestSuite;
  
  /**
   * Tests for {@link ExtensionRegistryFactory} and the {@link ExtensionRegistry} instances it
   * creates.
   *
   * <p>This test simulates the runtime behaviour of the ExtensionRegistryFactory by delegating test
   * definitions to two inner classes {@link InnerTest} and {@link InnerLiteTest}, the latter of
   * which is executed using a custom ClassLoader, simulating the ProtoLite environment.
   *
   * <p>The test mechanism employed here is based on the pattern in
   * {@code com.google.common.util.concurrent.AbstractFutureFallbackAtomicHelperTest}
   */
  public class ExtensionRegistryFactoryTest extends TestCase {
  
    // A classloader which blacklists some non-Lite classes.
    private static final ClassLoader LITE_CLASS_LOADER = getLiteOnlyClassLoader();
  
    /**
     * Defines the set of test methods which will be run.
     */
    static interface RegistryTests {
      void testCreate();
      void testEmpty();
      void testIsFullRegistry();
      void testAdd();
      void testAdd_immutable();
    }
  
    /**
     * Test implementations for the non-Lite usage of ExtensionRegistryFactory.
     */
    public static class InnerTest implements RegistryTests {
  
      @Override
      public void testCreate() {
        ExtensionRegistryLite registry = ExtensionRegistryFactory.create();
  
        assertEquals(registry.getClass(), ExtensionRegistry.class);
      }
  
      @Override
      public void testEmpty() {
        ExtensionRegistryLite emptyRegistry = ExtensionRegistryFactory.createEmpty();
  
        assertEquals(emptyRegistry.getClass(), ExtensionRegistry.class);
        assertEquals(emptyRegistry, ExtensionRegistry.EMPTY_REGISTRY);
      }
  
      @Override
      public void testIsFullRegistry() {
        ExtensionRegistryLite registry = ExtensionRegistryFactory.create();
        assertTrue(ExtensionRegistryFactory.isFullRegistry(registry));
      }
  
      @Override
      public void testAdd() {
        ExtensionRegistryLite registry1 = ExtensionRegistryLite.newInstance();
        NonNestedExtensionLite.registerAllExtensions(registry1);
        registry1.add(NonNestedExtensionLite.nonNestedExtensionLite);
  
        ExtensionRegistryLite registry2 = ExtensionRegistryLite.newInstance();
        NonNestedExtension.registerAllExtensions((ExtensionRegistry) registry2);
        registry2.add(NonNestedExtension.nonNestedExtension);
  
        ExtensionRegistry fullRegistry1 = (ExtensionRegistry) registry1;
        ExtensionRegistry fullRegistry2 = (ExtensionRegistry) registry2;
  
        assertTrue("Test is using a non-lite extension",
            GeneratedMessageLite.GeneratedExtension.class.isAssignableFrom(
                NonNestedExtensionLite.nonNestedExtensionLite.getClass()));
        assertNull("Extension is not registered in masqueraded full registry",
            fullRegistry1.findImmutableExtensionByName("protobuf_unittest.nonNestedExtension"));
        GeneratedMessageLite.GeneratedExtension<NonNestedExtensionLite.MessageLiteToBeExtended, ?>
        extension = registry1.findLiteExtensionByNumber(
            NonNestedExtensionLite.MessageLiteToBeExtended.getDefaultInstance(), 1);
        assertNotNull("Extension registered in lite registry", extension);
  
        assertTrue("Test is using a non-lite extension",
            GeneratedMessage.GeneratedExtension.class.isAssignableFrom(
            NonNestedExtension.nonNestedExtension.getClass()));
        assertNotNull("Extension is registered in masqueraded full registry",
            fullRegistry2.findImmutableExtensionByName("protobuf_unittest.nonNestedExtension"));
      }
  
      @Override
      public void testAdd_immutable() {
        ExtensionRegistryLite registry1 = ExtensionRegistryLite.newInstance().getUnmodifiable();
        try {
          NonNestedExtensionLite.registerAllExtensions(registry1);
          fail();
        } catch (UnsupportedOperationException expected) {}
        try {
          registry1.add(NonNestedExtensionLite.nonNestedExtensionLite);
          fail();
        } catch (UnsupportedOperationException expected) {}
  
        ExtensionRegistryLite registry2 = ExtensionRegistryLite.newInstance().getUnmodifiable();
        try {
          NonNestedExtension.registerAllExtensions((ExtensionRegistry) registry2);
          fail();
        } catch (IllegalArgumentException expected) {}
        try {
          registry2.add(NonNestedExtension.nonNestedExtension);
          fail();
        } catch (IllegalArgumentException expected) {}
      }
    }
  
    /**
     * Test implementations for the Lite usage of ExtensionRegistryFactory.
     */
    public static final class InnerLiteTest implements RegistryTests {
  
      @Override
      public void testCreate() {
        ExtensionRegistryLite registry = ExtensionRegistryFactory.create();
  
        assertEquals(registry.getClass(), ExtensionRegistryLite.class);
      }
  
      @Override
      public void testEmpty() {
        ExtensionRegistryLite emptyRegistry = ExtensionRegistryFactory.createEmpty();
  
        assertEquals(emptyRegistry.getClass(), ExtensionRegistryLite.class);
        assertEquals(emptyRegistry, ExtensionRegistryLite.EMPTY_REGISTRY_LITE);
      }
  
      @Override
      public void testIsFullRegistry() {
        ExtensionRegistryLite registry = ExtensionRegistryFactory.create();
        assertFalse(ExtensionRegistryFactory.isFullRegistry(registry));
      }
  
      @Override
      public void testAdd() {
        ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance();
        NonNestedExtensionLite.registerAllExtensions(registry);
        GeneratedMessageLite.GeneratedExtension<NonNestedExtensionLite.MessageLiteToBeExtended, ?>
            extension = registry.findLiteExtensionByNumber(
                NonNestedExtensionLite.MessageLiteToBeExtended.getDefaultInstance(), 1);
        assertNotNull("Extension is registered in Lite registry", extension);
      }
  
      @Override
      public void testAdd_immutable() {
        ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance().getUnmodifiable();
        try {
          NonNestedExtensionLite.registerAllExtensions(registry);
          fail();
        } catch (UnsupportedOperationException expected) {}
      }
    }
  
    /**
     * Defines a suite of tests which the JUnit3 runner retrieves by reflection.
     */
    public static Test suite() {
      TestSuite suite = new TestSuite();
      for (Method method : RegistryTests.class.getMethods()) {
        suite.addTest(TestSuite.createTest(ExtensionRegistryFactoryTest.class, method.getName()));
      }
      return suite;
    }
  
    /**
     * Sequentially runs first the Lite and then the non-Lite test variant via classloader
     * manipulation.
     */
    @Override
    public void runTest() throws Exception {
      ClassLoader storedClassLoader = Thread.currentThread().getContextClassLoader();
      Thread.currentThread().setContextClassLoader(LITE_CLASS_LOADER);
      try {
        runTestMethod(LITE_CLASS_LOADER, InnerLiteTest.class);
      } finally {
        Thread.currentThread().setContextClassLoader(storedClassLoader);
      }
      try {
        runTestMethod(storedClassLoader, InnerTest.class);
      } finally {
        Thread.currentThread().setContextClassLoader(storedClassLoader);
      }
    }
  
    private void runTestMethod(ClassLoader classLoader, Class<? extends RegistryTests> testClass)
        throws Exception {
      classLoader.loadClass(ExtensionRegistryFactory.class.getName());
      Class<?> test = classLoader.loadClass(testClass.getName());
      String testName = getName();
      test.getMethod(testName).invoke(test.newInstance());
    }
  
    /**
     * Constructs a custom ClassLoader blacklisting the classes which are inspected in the SUT
     * to determine the Lite/non-Lite runtime.
     */
    private static ClassLoader getLiteOnlyClassLoader() {
      ClassLoader testClassLoader = ExtensionRegistryFactoryTest.class.getClassLoader();
      final Set<String> classNamesNotInLite =
          Collections.unmodifiableSet(
              new HashSet<String>(
                  Arrays.asList(
                      ExtensionRegistryFactory.FULL_REGISTRY_CLASS_NAME,
                      ExtensionRegistry.EXTENSION_CLASS_NAME)));
  
      // Construct a URLClassLoader delegating to the system ClassLoader, and looking up classes
      // in jar files based on the URLs already configured for this test's UrlClassLoader.
      // Certain classes throw a ClassNotFoundException by design.
      return new URLClassLoader(((URLClassLoader) testClassLoader).getURLs(),
          ClassLoader.getSystemClassLoader()) {
        @Override
        public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
          if (classNamesNotInLite.contains(name)) {
            throw new ClassNotFoundException("Class deliberately blacklisted by test.");
          }
          Class<?> loadedClass = null;
          try {
            loadedClass = findLoadedClass(name);
            if (loadedClass == null) {
              loadedClass = findClass(name);
              if (resolve) {
                resolveClass(loadedClass);
              }
            }
          } catch (ClassNotFoundException e) {
            loadedClass = super.loadClass(name, resolve);
          }
          return loadedClass;
        }
      };
    }
  }
  